Disorder of Executive Function of the Brain after Head Injury and Mild Traumatic Brain Injury - Neuroimaging and Diagnostic Criteria for Implementation of Administrative Support in Japan

Survey on diagnosis of post-brain injury "higher brain dysfunction" in patients with cognitive impairment. Family/caregiver response

In Japan, the diagnostic criteria for the higher brain dysfunction (HBD) emerged in 2005 in response to social needs for support for the patients and their families. The issue of cognitive dysfunction after brain trauma is not unique to Japan. The purpose of this study was to reveal the current status of family members of HBD patients from their perspective, focusing on the changes before and after the establishment of diagnostic criteria in Japan. We conducted a questionnaire survey for family members supporting the HBD patients. The questionnaire included the causative condition, explanation on HBD by health professionals, and problems/difficulties they encountered. This research involved family members of 278 HBD cases (males = 211, age 49 years). The major underlying cause was head injury (n = 139). Compared to patients diagnosed pre-2005, a significantly larger proportion of family members after 2005 received information on the condition during the acute phase (within one month) (p < 0.001), including that from physicians (p < 0.001). Nearly half of the families cited a lack of awareness of HBD among the professionals as a problem. In Japan, awareness of HBD in the society is gradually increasing especially after the current diagnostic criteria were implemented, and there has been a steady increase over time in early diagnosis. Yet, there still remain those not appropriately diagnosed. To salvage those patients and the families left behind, we are suggesting several recommendations to further augment clinical practice and the healthcare systems in Japan.

Paclitaxel Reduces Brain Injury from Repeated Head Trauma in Mice

Repetitive mild traumatic brain injury (rmTBI) is known to disturb axonal integrity and may play an important role in the pathogenic cascades leading to neurodegeneration. One critical approach to reduce the future onset of neurodegeneration is to intervene in this process at an early stage following a brain injury. Previously we showed that direct application of the microtubule-stabilizing drug, paclitaxel, on the brain following controlled cortical impact improved motor function and reduced lesion size. Herein, we extended these findings to a model of mild brain injury induced by repeated closed-skull impacts. Paclitaxel was administered intranasally to circumvent its poor transport across the blood-brain barrier. Mice received five mild closed-skull impacts (one per day for five days). Intranasal paclitaxel was administered once only, immediately after the first impact. We found that paclitaxel prevented injury-induced deficits in a spatial memory task in a water tread maze. In vivo magnetic resonance imaging (MRI) and positron emission tomography with 18F-flurodeoxyglucose (FDG-PET) revealed that paclitaxel prevented structural injury and hypometabolism. On MRI, apparent, injury-induced microbleeds were observed in 100% of vehicle-treated rmTBI mice, but not in paclitaxel-treated subjects. FDG-PET revealed a 42% increase in whole brain glucose metabolism in paclitaxel-treated mice as compared to vehicle-treated rmTBI. Immunohistochemistry found reduced evidence of axonal injury and synaptic loss. Our results indicate that intranasal paclitaxel administration imparts neuroprotection against brain injury and cognitive impairment in mice. The results from this study support the idea that microtubule-stabilization strategies hold therapeutic promise in mitigating traumatic brain injury.

Imaging of Brain Trauma

Conventional imaging in the acute setting of brain trauma, relevant pathophysiology of injury, and advanced imaging techniques that may provide value in understanding the immediate management and long-term sequela of traumatic brain injury are reviewed. Key imaging findings that can guide clinical management related to such injuries as concussions, hematomas, dissections, dural atrioventricular fistula, and diffuse axonal injury are discussed. The role and accuracy of computed tomography, dual-energy computed tomography, computed tomography angiography, and magnetic resonance angiography in the acute setting are evaluated. In addition, caveats related to imaging the elderly and pediatric population are addressed.